1. Field of the Invention
The present invention relates to a projector device adapted to guide light from a light source to an optical system to generate image light for magnification projection on a forward screen.
2. Description of Related Art
Conventionally known as a projector device of this type is a liquid crystal projector device adapted to separate white light emitted from a light source into three primary colors of blue, green, and red for incidence on three liquid crystal panels for three primary colors, to synthesize the light transmitted by each of the liquid crystal panels with a color synthesis prism to generate a color image, and to magnifyingly project the color image on a forward screen with a projection lens.
With the conventional liquid crystal projector device, a polarizing plate is arranged at a light incidence side of each of the liquid crystal panels. Each liquid crystal panel and polarizing plate will generate heat upon receipt of light from the light source. Because high temperature liquid crystal panels and polarizing plates degrade optical properties thereof, the conventional liquid crystal projector device is provided with a cooling unit for cooling the liquid crystal panels and the polarizing plates. The cooling unit includes cooling fans respectively exclusively provided for the liquid crystal panels and polarizing plates for respective colors (see JP 2002-357865, A).
With the conventional liquid crystal projector device, the polarizing plates include a glass base material and a synthetic resin polarizing film joined to a surface thereof. Because the polarization function significantly degrades if the temperature of the polarizing film exceeds a limit temperature, the polarizing plates need to be cooled in order not to exceed the limit temperature. However, the polarizing plates easily have a high temperature because they have a small heat capacity, as well as because they are arranged at light incidence sides of the respective liquid crystal panels and therefore receive stronger light than light received by the liquid crystal panels. It is necessary in the conventional liquid crystal projector device to rotate the cooling fans of the cooling unit at a high speed in order to keep the temperature of the polarizing film within a limit temperature. This has resulted in a problem of increased noise occurring from the cooling unit.